1. Field of the Invention
The present invention relates to a keyboard for computers, and more particularly to a backlighting keyboard with a compact structure.
2. Description of Related Art
A keyboard for computers is generally provided with a backlight source so that it may be used in a low-light environment.
With reference to FIG. 6, a conventional backlighting keyboard has a metal substrate (80) made by means of a punching process. The metal substrate (80) has multiple pairs of L-like first lugs (81) and multiple pairs of second lugs (82) corresponding to keys (not shown).
A membrane printed circuit board (83) is disposed on the metal substrate (80), and a rubber button sheet (84) is disposed on the membrane printed circuit board (83). The membrane printed circuit board (83) has multiple nodes (831) corresponding to the keys. Multiple rubber buttons (841) are formed on the sheet (84) and respectively aligned with the nodes (831). The first lugs (81) and second lugs (82) in turn extend through the membrane printed circuit board (83) and rubber button sheet (84). Each of the keys is pivotally mounted on the respective first lug (81) and second lug (82) by a bridge (not shown). The rubber buttons (841) respectively abut the keys.
A light guide board (85), an illuminating board (86), and a bottom plate (87) are in turn provided beneath the substrate (80). The light guide board (85) has a light refracting area (851) formed at a bottom surface thereof. A backlight source being composed of multiple illuminants (861) is provided on the illuminating board (86). The bottom plate (87) is made of metal to stably support the illuminating board (86), light guide board (85), substrate (80), printed circuit board (83), and the rubber button sheet (84).
In use, backlights are emitted by the illuminants (861) and refracted by the light refracting area (851) to illuminate the keys so as to use the keyboard in a dark surrounding.
However, the conventional keyboard has some shortcomings as follows:
1. The substrate (80) is a thin metal sheet with multiple holes for backlights to pass through, so the substrate (80) has a low strength and may be easily deformed to become a wave-like shape during assembly and transporting.
2. In a case of the substrate (80) being deformed as a wave-like shape, the rubber buttons (841) cannot sensitively touch the nodes (831) when they are pressed downwards.
3. Because the substrate (80) is slidable about the light guide board (85), the light guide board (85) may be damaged by the friction between the substrate (80) and the light guide board (85).
Therefore, the invention provides a backlighting keyboard to mitigate or obviate the aforementioned problems.